MULTIPLE VALUE LIGHT INTENSITY MODULATOR

摘要

PROBLEM TO BE SOLVED: To provide a multiple value light intensity modulator capable of generating a PAM (pulse amplitude modulation) signal by conventional and simple combination of only binary electric signals without requiring a complicated drive by a driver circuit for driving a light intensity modulator.SOLUTION: The multiple value light intensity modulator is formed by interconnecting in series a plurality of Mach-Zehnder modulators having a light intensity modulator of an electric field absorption type in at least one of two arm waveguides. The branch ratios and multiplexing ratios in branch apparatuses and multiplexers of the plurality of Mach-Zehnder modulators are set different from each other, and ON/OFF control is performed in the light intensity modulator of the electric field absorption type, thereby controlling the light intensity of the output light to a multiple-value discrete value.